


fallacy

by honeybakedgrace



Series: to heretics and their devotions [2]
Category: Haikyuu!!
Genre: Alternate Universe - Assassins & Hitmen, Alternate Universe - Royalty, Falling In Love, M/M, Mentions of Death, Miya Atsumu/Sakusa Kiyoomi (mentioned), POV Multiple, Themes of Violence
Language: English
Status: Completed
Published: 2020-06-02
Updated: 2020-06-02
Packaged: 2021-03-02 19:55:04
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,911
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24482386
Author URL: https://archiveofourown.org/users/honeybakedgrace/pseuds/honeybakedgrace
Summary: Osamu swears to himself, day and night, that it’s just a shallow infatuation. He says it over his breakfast and before bed; a sinner offering penance to an empty confessional. He says it once, twice, three times a day, every hour on the hour, and when the sun is midway across the sky— but it’s never enough.
Relationships: Miya Osamu/Suna Rintarou
Series: to heretics and their devotions [2]
Series URL: https://archiveofourown.org/series/1770271
Comments: 27
Kudos: 259
Collections: OsaSuna Week 2020





	fallacy

**Author's Note:**

  * For [bastigod](https://archiveofourown.org/users/bastigod/gifts).



> OsaSuna Week 2020- Day 2, Tier 1: midnight/secrets
> 
> This work is a continuation of my previous fic ‘heresy’, featuring the beginnings of SakuAtsu’s storyline in this tale. I strongly recommend you read that first before diving into this!
> 
> This idea vaguely popped into my head when I was originally conceptualizing heresy and when I saw the prompts for OsaSuna Week I knew I had to flesh it out! Just like its predecessor, this fic is dedicated to Basti because he still endlessly supports me and the original! Here’s hoping this continuation is just as special! 
> 
> ALSO super special thank you to Rachel for kindly beta-reading and keeping my secret while I worked away on this! You are the best :p

**__**

**_3 months ago_**

 **  
**

In the dead of night, Osamu peers down at his pocket watch with his heart in his gut. The minute hand slides over the 12, forming a single needle pointing true north towards the fortress ahead as the second hand rushes on. One, two, three, four beats of the watch thrumming in time to his racing heart.

He folds the watch shut and pockets it, hoping the evening will cool the heat on his cheeks. Normally he’d be unconcerned, ‘Tsumu is a grown adult— certainly a dumbass but admittedly not entirely incompetent. (‘Admittedly’ as in a silent and begrudging admission inside Osamu’s head never to be spoken out loud—Atsumu is like some sort of vain deity in that every time someone so much as speaks his name in praise he doubles in ego and power. Osamu regrets comparing Atsumu to a god but the way he self-confidently sends people’s lives into turmoil sure does reek of divinity. ) But tonight there’s something different in the air; ever since seeing the uncharacteristically fiendish—yes, ever for her— glint in Hikari’s eyes sending ‘Tsumu off tonight, his mind’s been burdened with worry. 

He’s so deep in thought that Osamu nearly shouts when Suna wordlessly climbs onto the driver’s bench with him. 

“ _Fuck_ , Rin.” Suna presses a bare hand up to Osamu’s heart and snickers.

“Some heir you are gettin’ scared by little ol me,” he chides teasingly. “Aran told me the other one is on some sorta suicide mission?” 

“‘S not a suicide mission!” Osamu defends, a bit too loud. Suna presses a bony finger up to his wind-chapped lips and sushes him softly. 

“I’m fuckin’ with you ‘Samu,” he swats at Osamu’s temple, “is this what it’s gonna be like with you in charge? Worryin’ all the time like you got a stick up your ass in the un-fun way?” 

“Mm whatever,” Osamu grunts, scrunching his nose up at the way Suna kicks up both heels onto the footboard and slumps low in his seat. Suna twirls a thumb-sized blade between his long, thin fingers, letting it ride across his knuckles, back and forth, back and forth, back and—

“Can you stop that?” Suna tilts his head towards Osamu and looks up at him through narrowed eyes and a stripe of kohl eyeliner. 

“What?” Suna glances towards Osamu’s fidgeting leg setting an offbeat melody against the carriage’s footboard. “Sorry.” He grumbles, pulling his coat tighter around his big chest. 

“If you’re so worried then go check on him,” Suna offers. 

“Maybe you’re right,” Osamu muses, suddenly entranced by the hope of seeing his brother preening around the ballroom, safe. He swiftly rises to his feet, chest puffed out with bravado. 

“Osamu,” Suna tugs on his sleeve, “Osamu! Miya!” He calls as Osamu slides down from the driver’s seat and wraps around the front of the carriage towards the castle down the road from the now abandoned bakery they’re parked behind. 

Suna considers leaving him to his own devices— Osamu won’t die learning to keep his fingers out of Atsumu’s messes. Nonetheless he hops down and jogs after him, sticking to the shadows along the storefronts.

…

Osamu makes quick work moving towards the castle, the cover of night casting curling swathes of darkness through the empty streets. Music caught on the wind can be heard from the ball; the faintest whine of a violin in its final notes whistles through the silent night. By this time, intoxication is setting in, ankles go wobbly on precariously thin high heels, hands fist into silk robes and taffeta skirts— it’s the stroke of midnight that Rintarou loves best.

When party goers are starting to lose touch with time and reality, the night begins to feel endless. In the face of eternity people get bold and foolish. Rintarou revels in watching masks fall to the side and true colors paint even the blackest nights in brilliant color. 

_Beautiful, and barbaric._

Rintarou slinks behind Osamu while he stalks the perimeter for an appropriate opening to cross the wall. It’s serendipitous that he packed his good knives, but when it comes to the Miyas it’s a safe bet to expect some sort of trouble is nothing but a single, easily-scaled castle wall away. 

He likes watching Osamu work. He’s methodical and calculated, but he’s still a _Miya_ which means he’s dumb enough to take risks he doesn’t think through. 

People might be inclined to think Osamu is smarter, but Rintarouu knows he’s just lucky. Whatever happened before they were born predisposed Osamu to fortune, and thus Atsumu to misfortune. (Maybe it was what happened at birth: a firstborn’s beginner’s luck.) 

It tugs a grin across his thin lips when Osamu clambers up the shortest section of the wall, and the guard pacing towards him trips briefly over a stray pebble on the patrol path, allowing him to sail over the wall unseen and into the courtyard with nothing but a soft _thump_. 

Rintarouu waits for the guard to pass and follows suit, deftly leaping onto the walkway and over to the other side, missing the hunched form with a splash of gray hair by mere inches. He settles back on his haunches and mulls over one of his knives that’s starting to dull along the tip while Osamu runs over the castle ground’s layout in his head. 

“Osamu.” 

“What?” He seethes, tongue stuck between his teeth which can only mean he’s trying to remember something that’s long forgotten. Rintarou casts a finger in the direction of a hallway running along the western wall. 

“Tower’s southwest.” 

“Right, of course.” Osamu tugs up his hood, and starts to launch out of his squat before Rintarou’s arm whips out and clamps down on the back of his cloak and shirt, pulling him low into the shrubbery. He presses the flat side of his dagger to Osamu’s lips as two servants, shoulder to shoulder, stroll through the open hallway across the courtyard. 

“What would I do without ya, Rin?” Osamu breathes bitterly. 

Rintarou grins, his teeth and eyes flashing bright in the bare candle light of the sconces nearby. He says, “Surely, you’d be royal’s food by now,” tongue darting out to his lips with an amused smirk. 

Osamu nods, shaking his focus from the wetness clinging to Rintarou’s lips. 

The pair of them slip into the hallway, pausing to listen for the telltale patter of servants’ slippers before entering. Once they’re inside, there’s no turning back, not once they’ve passed the second, third, fourth, and fifth forks. Rintarou brushes his fingers along the wall, inking a map of the castle interior into his head as they go.

He whispers instructions into Osamu’s ear, clinging to any shadows in sight and moving quick and quiet through the maze sprawling out nearly a half mile in either direction. Finally, Rintarou catches sight of the looming tower, glowing faintly from it’s few windows on the top floor. 

“Shouldn’t the prince be at the party?”

“Wha—” Osamu swings his head to squint at the faint light flickering far above. “Could be ‘Tsumu.” 

“Could be,” Rintarou echoes. When the twins are willing to put their faith in ‘could be’s’ or ‘what if’s’, chaos is certain to follow. He only hopes that tonight isn’t the night it comes back to call for one—or both— of them. 

A thicket of bushes and ferns and flowers overflowing with life stretches out along the courtyard below the prince’s tower. Rintarou leads by snaking through a narrow slit in the greenery between two dense shrubs. The rough edges of the leaves and young branches nip and scratch at their cheeks, and Rintarou pulls his hood tighter in around his face. Osamu curses under his breath with each snap and rustle, trying and failing to match Rintarou’s utterly silent presence. As they near the tower, the opening widens, allowing them to move shoulder to shoulder under the cover of hanging willow tree branches.

“How the hell do they keep this stuff alive?” Osamu grumbles, tossing a snapped twig over his shoulder. 

“Prolly something to do with all those unlit lamps,” Rintarou points to the assortment of low and high hanging oil lamps, and then overhead to the notches in the wall. “And it looks like they can set up tarps to block out snow or heavy rain.”

“Seems like a lotta work for some plants.” 

“Anything for the prince I suppose,” Rintarou muses. He guides them to the threshold of a small opening back onto the garden path, with just enough visual clearance to get an eye on the tower’s largest window. “What exactly are you expecting to see, ‘Samu?” 

“Somethin’ to prove to me he’s at least alive.” 

“And what, he'll just appear in the window to wave at us and give us a thumb’s up? We don’t even know that the prince is up there, could be servants for all we know.” Osamu turns on Suna with a threatening finger and a scowl.

“Look if yer gonna be bitter and complain then ya can just go! I don’t need ya—” 

“Osamu.” Rintarou casts a finger up towards the tower, a breathy chuckle on his lips. 

Osamu glances up and inhales with a grimace, the naked figure of one Atsumu Miya with his back pressed into the window pane, two large, gloved hands splayed across his shoulders. 

“Well good news, we found your brother _and_ the prince!” Osamu pinches the bridge of his nose and exhales sharply. “I admit, I was wrong, you were right! Not the image I had in mind but he’s certainly alive isn’t he?” 

“I’ve got a terrible memory but I’m suddenly wishin’ I had no memory at all,” he whines. 

“If only the maps of castle’s grounds could have the longevity of ‘Sumu’s ass.” 

“Shut yer mouth, shut up,” Osamu begs. Rintarou cackles, enjoying the scarlet wash of embarrassment that blooms from his ears down to his neck. 

“Can we go back to the carriage now, Osamu? I think Atsumu’s got this one handled, or at least someone’s _handlin’_ it for him.” 

“Please,” Osamu whimpers, shaking his head and shivering with waves of regret. “‘M only ever listenin’ to ya from here on out.” 

“ _Told ya_ ,” Rintarou teases, throwing an arm around his shoulders. “Just listen to me and I’ll take good care of you, ‘Samu.” 

“Whatever, just get me outta this hellscape before I yak into the prince’s good ferns.”

——————————

**__**

**_2 and ½ months ago_**

 **  
**

Rintarou slides through the milling crowd, coming to rest his chin on the shoulder of a hunched over and especially quiet Osamu Miya.

He acknowledges Suna’s presence with a weak grunt, gently resting his head onto Suna’s in response. 

Osamu says, “Haven’t seen ya all night.”

Rintarou shrugs, “I figured someone else vyin’ for your attention would be a bit overwhelmin’.”

“I could’a used ya.” 

“I’m sorry.” 

“‘S fine.” Osamu runs the flat of his thumb along his wine glass, methodically making foggy streaks along the curve of it. 

“How are you?” Though Rintarou can’t see it, he can feel Osamu’s mouth curl downward into a bitter frown. 

_Why’re ya askin’ me that? Ya already know what ‘m thinkin’._

Nonetheless, Osamu forces a hollow laugh and says, “Well I can’t say I’m surprised ‘Tsumu was willing to give it all up for, _y’know_ ,” he gestures widley. 

“Osamu,” Rintarou looks up at him through dark lashes, serious. It’s eerie. “You don’t have to do that y’know. You can grieve.” 

Osamu lifts his head up to glance down at Suna. For the first time in his life, Rintarou can’t tell what he’s thinking.

“Ya, I know.”

——————————

**__**

**_2 years ago_**

 **  
**

It’s times like this Osamu recalls how unfit for his position he really is. Obedience makes up for most of his faults, at least in his mother’s eyes. She’s never cared for power or skill as long as her name lives on, and Osamu has the face to carry it.

It’s not the stiff handshakes and disingenuous congratulations from his peers that turns his mood sour, it’s the starving look in Hikari’s eyes as she watches him do so. She might as well have the business end of her blade dug into the small of his back. That’d be preferable to the weight of her gaze dragging his shoulders forward into an unseemly slouch. 

From what his mother claimed, the announcement of his official ‘coronation’ was going to be a celebration, but the mild-mannered gathering boasts no festivity. 

He’s not sure what sort of delusion he was living in to think otherwise; none of his duties as his mother’s successor could or would be considered fun. ‘Sumu got the lucky lot in life— his mistakes are mundane occurrences. If anyone else had accidentally burned down Duke Wakatoshi’s summer home it would have been the last light they ever saw. All he earned was a week on house arrest and a stern glare. While a glare from Hikari _could_ kill a man, ‘Sumu became immune to her sting over time. That or his skull is so dense not even she could hope to pierce through it. 

He mulls over these thoughts and walks the perimeter of the room, happy enough to keep his feet busy if not his mind. 

“Osamu!” 

He looks up to see Suna diving between the crowd, waving a bottle of something syrupy and dark. 

“Rin what did you—” 

“Honey whiskey,” he grins, leaning in just close enough that Osamu inhales the scent of it from his tongue, hot and sweet against his throat. He blinks twice, and Suna’s snakes his arm around his shoulders and tugs him out of the tent. 

They wander towards the edge of the empty market, sitting side by side on a makeshift bench of soggy rice bags. Suna passes the bottle, watches Osamu take a long, slow swig then takes it back, wrapping his long fingers around the cool glass. 

“Some party, huh?” Suna snickers, taking a sip and setting the bottle between them. “ _Prince Osamu_.” He sneers.

Osamu winces. “Not ya too, please not ya too,” he begs, reaching for another drink. 

“Nah I don’t see you that way,” Suna assures him, “To me you’ll always be Osamu the kid who fell face first into horse shit that one summer.” 

“Is it too late to switch back to prince?” Suna swipes the bottle and leans in close. 

“Yep.” 

Even drunk and sleepy Suna’s gaze still bores into Osamu with blinding intensity. He’s always saying something in those yellow irises. 

“Where’d ya get ahold’a this?” Osamu hoists the bottle to eye level, inspecting for a label or brand. 

“Your mom’s private stash of course.”

“Ya what?” He chokes out in disbelief, nearly dropping the bottle. 

“Don’t worry ‘bout it Osamu,” he waves his hand in a way that says, _don’t ask cause I won’t answer_. “Just enjoy it.” 

“Rin, d’ya have a death wish or are ya just stupid?” 

“Bit a both?” Osamu grumbles in agreement. 

“I sure wish ya’d care a bit more ‘bout yer own well-bein’, ‘specially when it comes to her.”

“Someone’s gotta knock her down a peg, eh?” Suna taunts, eyes alight with mischievous fervor. Osamu hesitates to agree; dissidence is not something that comes easy to him. Suna levels his gaze, knowing, understanding. 

Osamu says, “Quit lookin’ at me like that,” and pouts his bottom lip. 

“Like what?” Suna counters, not breaking contact. 

“Like yer cracking my head open and lookin’ inside.” 

“I’ll put it back the way I left it,” he promises with his tongue stuck in his cheek. “I don’t need to see in your head to know what you’re thinkin’ ‘Samu.” 

“Thought ya said I was infallible.” 

“Thinkin’ it and sayin’ it are two entirely different things. Instinct versus action. And I’ve never known you to act on instinct.” Suna takes a sip. “I’ll never know what you’re actually doin’ next.” 

Osamu stays silent, thinking too hard about how to respond correctly. As if when it comes to Suna there is a wrong way. 

“Osamu,” he looks up through a fringe of sweat-slicked bangs, the alcohol leaving him flushed and dizzy, “is this even what you want?” 

In 23 years no one bothered to ask anything of the sort. No one in Darkwell was wasting their breath asking something that could get their throat slit if they asked it too loudly. 

Having someone risk their throat just to ask you something they and you already know the answer to, just for the sake of letting you finally admit that no, you don’t want this, makes Osamu’s heart sing so loud nobles would dance to it. 

“No,” he admits. ‘No’ might be just as tempting a thing to let past his lips as the boy sitting next to him. “No, I don’t.” 

“But what does it matter, right?” Suna knocks back the final drizzle of honey whiskey and rolls the bottle aside. He messily wipes it from the corners of his mouth before leaning on his hands and letting his head lull back. Even intoxicated he’s unerring. 

“Right.” 

“You’re as infallible as always Osamu,” he chuckles. Osamu regards the laugh that slips from his lips, unmistakably bitter.

“I could say the same about you, Rin.” Suna meets his pointed gaze and cracks with just a hint of surprise. 

“Mmm,” he hums, leveling Osamu’s emboldened expression. “Not as infallible as you think.” 

Osamu lets himself lean in, daring for a second to indulge in a fantasy of choice. Suna lets him. He doesn’t hold his breath for Osamu to finish what he’s started, because by the time his breath is tickling Suna’s ear he realizes he’s entertained those pervasive thoughts for far too long already. 

Osamu stands quietly, fetches the mud-slick empty bottle and nods towards Suna. “Night, Rin,” he bids before slipping back into the tent via the slit they left from. Osamu shakes off the imagined sensation of Rintarou on his lips and disposes of the empty bottle; not even the finest honey whiskey could allow him to nourish such a notion. 

Two winters from now Osamu will begin the process of taking his mother’s ‘throne’. Suna Rintarou will just be an inkblot in the margins of his journal. Rinse. Repeat.

——————————

**__**

Of course, two winters pass and of course, even the best-laid plans are victim to the unpredictability of young love.

Osamu swears to himself, day and night, that it’s just a shallow infatuation. He says it over his breakfast and before bed; a sinner offering penance to an empty confessional. He says it once, twice, three times a day, every hour on the hour, and when the sun is midway across the sky— but it’s never enough. What began as simple affection blossoms into passionate adoration. Osamu devotes himself more to Rintarou than to his apprenticeship, stumbling through briefings and strategy meetings and mission reports all while thinking about how good Suna would look in emerald green velvet robes under candle lit chandeliers. 

(Almost all of his fantasies include the two of them being somewhere else, far away from the clutches of reality, from the clutches of his mother.)

On a bitterly cold New Year’s Eve Osamu steals a midnight kiss behind the curtain of his bedroom. He tells Suna he likes him, Suna tells him liking people is for teenagers.

Meanwhile Hikari grips onto him even tighter, which only makes Osamu more keen to tear away. He stays for the sake of his brother, for the sake of Rin. 

Osamu wonders, when his bed cover is pulled overhead and he finally gets a few moments of peace from when Atsumu stops talking to when he starts snoring, what’d it be like to love Rintarou. 

Each time he gets close enough to dare, the words stuck between his clenched teeth, Hikari ’s voice reminds him, _You can never have him_. He believes her— or at least himself using her voice to justify his cowardice. 

It’s not as if he _can’t_ take a spouse, but through nurture and nature Osamu sees marriage as a clinical thing. Marriage is for people who want the tax benefits, for people who have nothing better to do than sign the papers. Love is altogether something entirely different. 

While he may be allowed to marry Rintarou, he would never be permitted to love him. 

So he tucks it under his chin, behind his ears, settles it into his ribs— a secret all his own. Not even looking at Atsumu with a head of honey blonde hair for the first time could make him feel so much like _himself_. Yet it still burns to watch Atsumu fawn over one suitor after the next, a painful truth that anything he has Atsumu could have better if he wanted it. 

Suna stays achingly close but accordingly distant. He keeps his hands to himself for the show but dares to push his luck in private. 

“Y’know,” he says, perched cross-legged on the wooden kitchenette, “if you don’t like all,” he waves his hand in a wide gesture, “ _this_ —”

“‘M not doin’ this with ya again,” Osamu huffs, slicing into a tomato with force. 

“ _Doin’ what_?” Suna teases. He deftly swipes a slice of tomato before Osamu can smack it out of his hand. “Delicious,” he says through a mouthful of it. 

Osamu warns, “Don’t change the subject.” 

“So you do wanna talk about it?” 

“God, Rin,” Osamu glares up at him, knife in hand, “ya can’t do this to me—and don’t say ‘do what’. Ya know damn well what.” Suna untucks his legs and lets them dangle from the counter, leaning his elbows forward on his knees and folding his long fingers together.

“Is it a crime to want that?” He muses softly. Osamu avoids his gaze and continues with the meal. 

“Course not,” he admits. “But wantin’ is all it is. All it can be.” 

“You’re always so caught up on those can be’s and could be’s ‘Samu,” Suna scoots closer until his thigh is brushing Osamu’s side. “We could get outta here.” 

“Y’know I can’t” Osamu reminds him. 

“Fine, Atsumu can come too.” 

“‘S not what I meant,” Osamu places the knife next to the cutting board and plants an arm on either side of Suna’s hips, pushing himself between Suna’s thighs. “She’ll find us anywhere. I can’t just run away from this.” 

“So you’re running away from this instead?” Suna cups his chin and presses a kiss to his barely parted lips. Osamu allows it, leans into it, encourages it.

“Yer very convincin’,” Osamu admits with a small chuckle, still winded from the kiss. He thumbs at Suna’s mouth, running the pad of his finger along his cheekbone and temple. “I’d do the job m’self if I thought I’d win. I just don’t wantcha to get hurt, Rin.” Suna sighs and leans into his touch.

“Too late.” 

Those were the darkest thoughts, terrifying admittances that Osamu would make his last job his own mother if given the chance. He hates it, hates the work, but something nasty in him knows that the only way to end it is to end her. So he waits, he waits for the day she hands over the torch and fades peacefully into the night and Osamu can finally, in her passing, do the thing she set out her entire life to prevent—burn the place to the ground. 

It’s satisfying and sickening to know his mother planted the seed of violence in him. He revels in the thought of being her own undoing, but wilts in knowing it’s only because he keeps some of her with him. 

He still recalls her lessons, branded into him whether he liked it or not.

“You see Osamu,” she said, chin tilted up, “everyone has one. No one is indestructible, no one is absolute. No one is free from fallacy, you just have to know how to find it.” 

“Fallacy,” he echoed. 

_Foolishness. Misconception. Assurance in false truths. Fallacy._

Images of Suna grinning and inching closer, pinkies intertwined beneath dinner tables, clumsy dances to the tune of melodic humming in the shadows of empty alleyways, rare kisses under blankets, shared handles of expensive mead, one indulgent night in the back of a stolen carriage, all the memories flashed behind his eyes. More secrets. Allowances to believe there’s a world where he could. Fallacies.

——————————

**__**

**_present day_**

 **  
**

Osamu drags his feet together and stands at attention. He suppresses a yawn and threads his fingers together behind his back. Hikari’s 3 A.M. emergency meetings are never pleasant, but the repercussions of absence would be far less preferable.

She paces tight circles, then straight lines. She paces often, so often Osamu is convinced the chair in her office space is just for decoration. From his memory of the past 23 years, he can count on his hands how many times he’s seen her sitting, and at least half of them were because she was asleep. 

She returns to circular paths while sleepy assassins filter in, lazily tucking in shirts and adjusting collars of their cloaks. Onlookers would be impressed by the formality of people who woke up from a dead sleep only minutes ago. 

Once the crowd seems to have settled, Osamu notes those present. Mostly high-ranking assassin’s, generals, and visiting governors (those in charge of distant headquarters). But Suna…

 _Rin._

Suna’s gone. It only seems right that the highest-ranked assassin in the Wrenia Guild would be present for the matter. Even more concerning that Hikari seems not to recognize his absence as she begins addressing the small crowd. 

Osamu tunes out most of the introductory nonsense, catching bits and pieces of the familiar words while he scours the area for any sign of Rintarou’s slick brown locks. 

“Gathered you all...discuss the matter at hand… act of treason tonight—” 

Osamu swings his head towards Hikari, _that’s new_. A murmur courses through the crowd, but falls to hush when she begins again. 

“It’s true,” she scans the crowd, intended to make each person feel watched, to feel exposed, “it was wrong of me to assume I was in company that could be trusted, that was my mistake.” Her eyes settle thoughtfully on Osamu— not doubting, curious, rather. “But it was far greater a mistake to cross me.” She disappears back into her quarters, leaving those present to whisper and wonder. Osamu’s heart drops in his chest. 

_‘S over. ‘M done fer_ —

Hikari reappears, pushing a tall shape in front of her, bound by his wrists. 

“Rin,” Osamu breathes, meeting his bitter gaze as Hikari swiftly kicks into Suna’s legs, sending him to his knees. 

“Our dearest ally Rintarou, made his choice to become our greatest enemy,” she paces behind him now, casting stray glances down in disgust. Suna keeps his eyes trained onto the ground. “It’s a shame, truly, to see such talent and tenacity go to waste.” A soft whisper of placated agreement washes over the group. “No assassin in any of the six kingdoms could hope to do what Rintarou attempted to accomplish tonight, all of you keep that in mind.” 

“One day, one of em will,” Suna mutters, which earns him a sharp kick in the spine. 

“As you all are aware the punishment for mutiny… is death.” She draws her balde from her side, glinting under the faint candlelight in the room. 

_Why’d he hafta go an get his hands dirty? If I stand up to her she’ll kill me too then we’ll both be dead and nuthin’ll change. If I_ —

Hikari raises her blade performatively, but lowers it, extending it towards Osamu. 

“Osamu,” she says, firm, certain, “it won’t be long until you are in my position, until you are the one under threat. Show them that you are ready. Show them you are not to be defied.” 

Osamu accepts the blade, stepping forward towards Suna with his heart in his throat. 

“I’ll take 'em down to the river. He doesn’t deserve a spectacle.” She nods, and Osamu reaches around to grasp Suna by his restraints harshly. Suna goes heavy in his grasp, but thankfully what Osamu lacks in dexterity he makes up for in brute strength. 

Once he’s dragged a stumbling Suna out of the camp, he begins to protest. 

“C’mon ‘Samu, we both know you’re not gonna kill me.” 

“Do I know that?” Osamu growls. “Why’d ya have to go an get yer stinkin’ hands into my shit.” 

“You’re the one always complain’ and never doin’ a damn thing about it.” 

“Ya dunno what ‘m doin’.” 

Past the campsite, further away from town, is the ragged Dunmont mountainside, where a half mile down a river cuts through its cragged peaks. Osamu pushes them further and further away from the campsite until the two of them are stumbling down the steep decline. 

“ _Yer right_ ,” Suna mocks, “I have no clue what you’re doin’, now let me go.” 

“Ya never even asked, if ya did then maybe this wouldn’t be happenin’.” 

“C’mon Osamu let me go,” he demands. 

“ _No_.” Osamu tightens his grip and continues dragging him down the mountain, now enveloped in the canopy of dark oak and pines, towering many meters above. 

“So what? You’re gonna kill me? Bein’ your mother’s bitch like you always have been?” 

Osamu grunts in response, tongue stuck between his teeth as he weaves through the dense forest. 

“You’re something else entirely, Osamu. Ever since Atsumu disappeared—”

“Don’t go talkin’ ‘bout ‘Tsumu so damn loud.” 

“What? Did you kill him too?” He taunts, writhing in Osamu’s grasp. 

“Rin—” 

“Don’t call me that,” Suna spits, teeth bared and snarling. “Don’t you fuckin’ dare.” 

“Suna, would’ja _just_ —” Osamu takes one hand and forces Suna’s chin up towards the canopy, “—shut yer trap and look?” 

Suna struggles, recoiling from his hand until a flicker of something golden catches his eye. He stills, focusing in on the spot in the trees. A dark form takes shape— a wooden shack nestled into the treetops, beautifully obscured by thick branches and dense greenery. 

“The hell is that?” He glances at Osamu out of the corner of his eye. 

“Me savin’ yer dumb ass, c’mon.” 

Osamu nudges him on towards a nearby pine, brings two fingers up to his mouth and whistles. A few beats pass and a rope ladder is slung from the treetop house down against the trunk of the massive pine. Osamu takes the blade in hand and sever’s Suna’s bindings in a single slice. 

Suna holds his hands up to his face in muted shock, looking in disbelief between the ladder and Osamu. 

“You let me believe you were gonna kill me.” 

Osamu swats him upside the head. “I was thinkin’ ‘bout it.”

Suna sticks his tongue out in defiance before starting to hoist himself up on the ladder, and Osamu follows suit. 

“Now what the hell is so damn important that ya had to wake us up in the middle a the night?” A matted bedhead of long blonde hair hangs out of a single window, shadowed by a taller figure standing with his arms wrapped around Atsumu’s torso. 

Suna leaps onto the landing and steps into the house while Osamu pulls up the ladder. 

“ _Atsumu_?” 

Atsumu, looking a bit thinner and more tired, stands in the center of the small shack with a dark-haired and sleepy crown prince of the Sakusa Kingdom clung to his back. Kiyoomi rests his head on Atsumu’s shoulder and mumbles something unintelligible into his ear. 

“Ya, I know baby we’ll go back to bed soon,” he murmurs, which seems to placate the bratty prince for the time being. 

“Aren’t you—” Suna reels from the onslaught of concerning revelations, still trying to process the last hour or so of his life. “‘Samu?” 

Osamu tromps through the doorway with a scowl before tossing the blade onto the small dining table. 

“Well knuckleheads, now ya got a new roommate,” he announces. “Rin, ya should prolly sit down, ‘s gonna be a lot.” He pulls a chair from the table and twists it around, sitting with his arms crossed over the backrest. Osamu huffs tiredly and sits down next to him, Atsumu remains standing with both hands on the arms snaked around him, rubbing circles with his thumbs methodically into mole-freckled skin. 

Osamu starts from the beginning, the night Atsumu disappeared. 

“An he came to my room in the middle a the night begging me to help him out cause the prince is so pretty an he can’t kill ‘em, blah, blah, blah.” 

Atsumu interjects, “I never _begged_ ,” flushing pink while Kiyoomi continues to bury his head into his shoulder. 

“Whatever, like I care, anyways—” 

Osamu recounts the plan, Kiyoomi’s childhood treehouse buried deep in the mountains—long abandoned and grown into the canopy from disuse. A place well-hidden enough in the first place from assassins to offer them their own head-quarters of operation. 

From there, the rumors of Atsumu’s disappearance spread on their own, and Hikari wasn’t going to raise a finger looking for him—which makes Atsumu admittedly bitter, eliciting a kiss into his neck that makes Osamu and Suna wince. 

“The plan from the beginnin’ was to take down Hikari, and it still is. I just couldn’t tell ya. It’s a risky mission, Rin. I didn’t wanna hurt ya.”

“Too late.” Osamu leans across the table and presses a kiss into Suna’s temple, thumbing back strands of hair around his face.

“But this doesn’t tell me anything about how you idiots are gonna take her out.” Suna reminds them. 

Atsumu grins, even Osamu reveals a small, knowing smile. 

“You have somethin’?” 

"Ya’ve heard her talk, all high and mighty about the foolishness of humans an how we always have a weak spot.”

“Obviously.” 

“Well, we got her’s. Her achy heel,” Atsumu boasts. 

Osamu exhales slowly, deeply. “Achilles heel.” 

“Who?” 

“Nevermind, point is, we got it.” 

“One fatal misconception,” Suna whispers, lips parted in awe. “You found it?” Osamu nods, Atsumu nods. 

“There’s one thing she’s always trusted as fact, one thing that she’s nurtured with the know-how on takin’ her down.” 

“And what’s that?” Osamu steps forward, arms crossed and eyes narrow. It’s more steeled resolve than Suna’s ever seen on him—and it’s admittedly the hottest thing Suna’s ever seen on him. 

“‘S me, of course.”

…

Osamu treks back up the mountainside once the snow is falling again. Even in early March, the fresh powder is able to seal up the path behind him, no trace of what happened in the hills tonight. He arrives at Hikari’s quarters in the bleary hours of the morning, when dawn is turning the black sky cobalt blue.

He recalls his lessons, recalls the immortal words that Hikari so carefully gifted to him for her own selfish gain. He repeats them over in his head when he steps into camp, and when he’s pushing open the door to her office. 

As expected, she’s standing behind her desk with palms flat on its surface. She glances up for only a moment to acknowledge Osamu’s presence before returning her attention to her work. 

“I assume you completed your work for the evening, hm?” 

_Foolishness._

Osamu presents the lock of rich brown hair and the blade, rinsed clean. 

_Misconceptions._

“Ever the good son, Osamu.” She twirls the lock in her fingers before unlocking a small, thin drawer and depositing it inside. “I always knew I could trust you.” 

_Assurances in false truths._

“Of course,” he says, “I’d never let ya down.” 

_Fallacy._

**Author's Note:**

> I went A BIT off the rails for this fic and really let myself have a lot of fun and indulge a story I’d personally love to read. After this installation, I have about a million hc’s and ideas that I’m dying to share so feel free to ask or even share your thoughts on how you think the story ends up! 
> 
> I also want to thank everyone for all the love I’ve received for heresy, I’ve had a handful of people tell me that is a SakuAtsu staple for them and a few that it got them into the ship and I’m so immensely proud of that. I hope fallacy lives up to that and it is a worthy continuation for those who loved the first. 
> 
> If you want to come and say hi or hear me talk your ear off about the world of to heretics and their devotions (I don’t bite I promise) I am @honeybakedyams on twitter!!


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